1. Field of the Invention
The present invention relates to a heat-resistant polyimide film, and more particularly, it relates to a new polyimide film and a process for producing the same, said polyimide film being improved in adhesive properties through the introduction of a special titanium-based organometallic compound which controls the surface forming process.
2. Description of the Prior Art
Polyimide film is known for its outstanding properties such as heat resistance, low-temperature resistance, chemical resistance, electrical insulation, and mechanical strength. It is widely used as heat insulation film, electrical insulating film, and base film of flexible printed-wiring board. In the last two application areas, polyimide film is usually bonded to a copper foil with an adhesive or coated with an adhesive. Therefore, the adhesive property is an important performance required for polyimide film.
The conventional technology for imparting adhesive properties to high polymer film includes flame treatment, corona treatment, UV rays treatment, alkali treatment, primer treatment, and sandblasting.
Polyimide film undergoes such conventional sandblasting and alkali treatment so that it meets the requirements for heat-resistant film.
Since these treatments are designed to be performed after the film has been completed, the adhesion strength achieved by the treatment varies depending on the adhesive properties of the original film and the uniformity of post treatment. Therefore, they are not suitable for producing film with improved adhesive properties. In addition, they lead to a cost increase because they need additional steps.